Looking for the right PSU, help?

[beefsupreme]

Here's the build I'm working on:

CPU - i7 950
GPU - Radeon HD 5870
Mobo - Gigabyte GA-X58A-UD3R
RAM - 3x2GB Corsair XMS3 DDR3 1600
HDD - Samsung Spinpoint F3 1TB
Case - HAF 922

In the future I plan to:

1. Overclock the CPU to about 4GHz.
2. Add in another 5870.
3. Overclock them both.
4. Add in another 6GB of RAM.

I'm just not sure where to start with picking the right PSU, and I trust you guys a lot more than myself. I'm willing to spend up to $150. Thanks!

 

[Timop]

I would get a 850W for the sake of security.

The XFX 850W is great for only $115 shipped AR:
http://www.newegg.com/Product/Product.aspx?Item=N82E16817207001&cm_re=XFX_PSU-_-17-207-001-_-Product

The TX950 is also great for only $120, more power but not modular: http://www.newegg.com/Product/Product.aspx?Item=N82E16817139013&Tpk=corsair%20TX950